SECM-based test system for corrosion of buried metal pipeline and stripping of anti-corrosion layer stripping

Abstract

The invention discloses an SECM-based test system for corrosion of a buried metal pipeline and stripping of an anti-corrosion layer. The ECM-based test system comprises an AC stray current loading system, an electrolytic tank system and a scanning electrochemical microscope test system, wherein the AC stray current loading system is used for providing an interference source of an AC stray currentfor the buried metal pipeline, the electrolytic tank system is used for simulating actual engineering conditions of the buried metal pipeline under different soil environments, and the scanning electrochemical microscope test system is used for acquiring a local microregion image and charge transfer characterstic of a breakage point of the anti-corrosion layer during the metal corrosion process under an effect of the stray current and analyzing data. The test system can be used for simulating local pipeline corrosion and stripping of the anti-corrosion layer caused by the stray current flowinginto / out of the breakage point of the anti-corrosion layer of the buried metal pipeline under different soil environments, stray current intensity, anti-corrosion layer types and breakage area ratiosof the anti-corrosion layer.

Description

technical field [0001] The invention relates to the technical field of corrosion and anti-corrosion layer peeling test of buried metal pipelines, in particular to a test system for corrosion and anti-corrosion layer peeling of buried metal pipelines based on SECM. Background technique [0002] External anti-corrosion coating technology is a very effective method to reduce the corrosion of buried metal pipelines and increase the service life of buried metal pipelines. The ideal anti-corrosion layer has no defects, and has the function of blocking and shielding the corrosive medium. However, due to the complexity of the coating process and mechanical collisions during the construction process, the anti-corrosion layer on the pipeline will inevitably have some defects such as pinholes and damage, or due to various defects in the soil during the long-term service process. The long-term effects of various corrosion factors lead to bond failure and then defects such as damage and...

AI Technical Summary

Problems solved by technology

The stray currents generated by electrified railways and high-voltage transmission lines have a serious impact on the safe operation of pipelines, especially for long-distance oil pipelines with defects such as damaged and peeled anti-corrosion coatings, which will form serious localized corrosion at the defects of the anti-corrosion coating And anti-corrosion layer peeling phenomenon, which seriously threatens the safe operation of the pipeline

[0003] Traditional metal corrosion mechanism research generally adopts macroscopic electrochemical testing methods, such as polarization curve method, AC impedance spectroscopy, corrosion potential and noise technology, etc. These traditional electrochemical testing methods obtain the macroscopic change results of the entire sample. Can not reflect the local corrosion information of the sample

Especially for buried metal pipelines with anti-corrosion layer, when the corrosion phenomenon occurs at the damaged point of the anti-corrosion layer, the traditional macroscopic electrochemical test method cannot detect the electrochemical information of the metal matrix / solution interface, and thus cannot reflect the metal The process of localized corrosion and anti-corrosion layer peeling and local characteristics

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